textproduct: Rapid City

KEY MESSAGES

- A cold front will move slowly across western South Dakota tonight, bringing chances for showers and thunderstorms. Severe severe storms are possible, especially over northwestern South Dakota.

- Cooler Monday, then hot again Tuesday.

- Slight chance for storms Monday, with higher chances for storms Tuesday night and Wednesday.

DISCUSSION

(This Afternoon Through Saturday) Issued at 1143 AM MDT Sun Jun 7 2026

Upper level analysis has a low over Alberta with a trough extending through the northern Rockies into the Desert Southwest. At the surface there is an area of low pressure over western North Dakota. A cold front extends southward from the low along the Montana/South Dakota border, into northeastern Wyoming, and down into northern Utah. This cold front will be the focus for convection later today.

Thunderstorms will form early this afternoon over northeastern Wyoming and move northeastward through the evening. Steep lapse rates, SB CAPE of 1500-2000 J/kg, and 0-6 km shear is 30-40 kts, indicates the possibility of severe storms later today and into the evening. However, the more favorable parameters for severe storms will likely be located further north - closer to the Montana/North Dakota border. As the potential for severe storms wane by late evening, scattered showers and storms will continue overnight across much of western South Dakota behind the cold front.

On Monday, it will be cooler with highs in the 70s to low 80s. Surface high pressure will slide through the CWA, resulting in increasing southeasterly winds of 15-25 mph during the afternoon over the northeastern Wyoming and far western South Dakota plains. Another hot day is ahead on Tuesday with prefrontal warming and gusty southerly winds. Highs will be back in the 90s. Due to the greenness from the recent rain, the NBM high temperatures are most likely a few degrees too high. Another cold front will move through the area late Tuesday and Wednesday, resulting in a chance for scattered storms, some of which may be severe closer to central South Dakota. Temperatures for the second half of the week will be closer to seasonal averages.

AVIATION

(For the 18Z TAFS Through 18Z Monday) Issued At 1143 AM MDT Sun Jun 7 2026

Isolated to scattered, potentially severe, thunderstorms will develop over northeast Wyoming early this afternoon before moving over southeast Montana and northwest South Dakota this evening and into the overnight hours. Large hail, frequent lightning, and gusty/erratic winds can be expected with any stronger convective cores. Transient MVFR/IFR conditions also expected around any heavier precipitation cores. Conditions will improve between 05-07z as storms/showers move out of the region.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.